String literal tokenizer

Tokenize a string that may contain double-quoted string literals and bare words separated by spaces. A string literal starts and ends with a double quote and supports backslash escapes inside: '\n' -> newline, '\t' -> tab, '"' -> a literal double quote, '\' -> a literal backslash; any other escape '\x' yields the character x literally. Bare words are maximal runs of non-space, non-quote characters. Spaces outside quotes separate tokens and are discarded. Return a list of the decoded token strings in order (quotes themselves are not part of the value). Assume every opened quote is closed. Empty or all-space input returns an empty list.